New Generator ATS (Automatic Transfer Switch) Wiring to existing Panel Board

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bbard

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Little Falls, NJ, USA
I installed my first Generac 16KW generator and 200 Amp Transfer switch. I failed the electrical inspection because I did not separate the ground and neutral wires in the existing panel board and did not include a ground wire in the SER cable from the transfer switch to the panel board.

The existing panel board is all plastic and I am using an SER cable between the ATS and panel board. I really don't see how an objectionable neutral current would be an issue. I am hoping that there is an NEC exception code to help me out. It is lots of re-work.

Please see a sketch attachment.

I really appreciate the help.
 

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SER cable has 4 conductors which includes a separate EGC. You should be able to separate the EGC bus and neutral bus in the existing panel. If it's actually SEU which is only 3 conductors then you'll need to change it. Also if you haven't done so already the existing GEC's need to be moved to the ATS.

Welcome to the Forum. :)
 
infinity said:
SER cable has 4 conductors which includes a separate EGC. You should be able to separate the EGC bus and neutral bus in the existing panel. If it's actually SEU which is only 3 conductors then you'll need to change it. Also if you haven't done so already the existing GEC's need to be moved to the ATS.

Welcome to the Forum. :)
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Just a point of clarification, I too always thought SER cable was only 4-wire/conductors. My supply house manager straightened that out for me. SER can be 3-wire/conductor. AFAIK, SEU is only 3-conductors or less.
 
Little Bill said:
Just a point of clarification, I too always thought SER cable was only 4-wire/conductors. My supply house manager straightened that out for me. SER can be 3-wire/conductor. AFAIK, SEU is only 3-conductors or less.
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You're correct, but around here I have never seen 3 conductor SER, hence my assumption. Maybe when bbard checks back in I'll be proven incorrect.
 
I took the OP to say that there is no EGC between the ATS and the panel, regardless of the type of cable he is indicating. I think it prudent to first determine if this is a SUSE rated ATS. If not he has other issues.
 
Welcome to the forum.

bbard said:
The existing panel board is all plastic and I am using an SER cable between the ATS and panel board. I really don't see how an objectionable neutral current would be an issue. I am hoping that there is an NEC exception.
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Nope. The ATS is now your main disconnect, and everything after it, like the panel, must be rewired as a sub-panel by separating the neutrals and the grounds. Technically, any neutral-using 3-wire major appliances (range, dryer, etc.) are supposed to be rewired as 4-wire, too.

The objectionable current would be any current on the bare conductor, rather than the insulated neutral conductor, in the service cable after the ATS. That's why everyone was confused by your 3-wire SER: we use SER to mean 4-wire cable. Sorry there are no exceptions here.

The ATS is rated for service use, isn't it?
 
LarryFine said:
Welcome to the forum.


Nope. The ATS is now your main disconnect, and everything after it, like the panel, must be rewired as a sub-panel by separating the neutrals and the grounds. Technically, any neutral-using 3-wire major appliances (range, dryer, etc.) are supposed to be rewired as 4-wire, too.

The objectionable current would be any current on the bare conductor, rather than the insulated neutral conductor, in the service cable after the ATS. That's why everyone was confused by your 3-wire SER: we use SER to mean 4-wire cable. Sorry there are no exceptions here.

The ATS is rated for service use, isn't it?
Click to expand...


The ATS is rated for service use. I now understand exactly what I have to do to fix my mistake. I ran a 4/0 two-conductor cable with a shield used for the neutral, instead of running a three conductor with ground SER cable and I did not separate the neutral and ground wires in the panel board. I also have to move the GEC from the panel board to the ATS. I really appreciate all the responses. This is an amazing forum with amazing professionals. God bless. :D
 
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